Method and device for folding up air bag, and air bag

ABSTRACT

An air bag is unfolded on a planar surface and is inflated with air. The air bag is loosely sandwiched between the upper and lower blades that are arranged in a radial configuration. Movable blocks progress toward the center to fold the upper and lower panels of the air bag against the central part of the air bag. The resulting central folded part of the air bag has a wave-like configuration, and the upper and lower panels are separated from each other. The ear-like portions of the air bag are wound around the central folded part of the air bag that is folded in a wave-like configuration. Then, the central part of the air bag is pressed downward to complete the folding process. Gas can be supplied smoothly from the inlet port to the periphery when the air bag is reinflated. The method for folding the air bag is simple, and the air bag can be inflated quickly.

FIELD OF THE INVENTION

The present invention relates to a method for folding an air bag thathas been inflated, for example, with gas; a device for folding an airbag; and an air bag.

BACKGROUND OF THE INVENTION

A conventional air bag device is provided on a steering wheel of anautomobile. This air bag device comprises an air bag having a flatbag-like configuration, a cover body for covering the air bag, and aninflator for injecting gas. The air bag is folded into a small size andis housed in the inside of the cover body by a predetermined method. Theair bag device injects gas from the inflator when the sensor detects animpact of a collision in order to inflate the air bag. The cover bodymust be broken with the inflation pressure of the air bag, allowing theair bag to be inflated and deployed toward the driver to minimize theforce of impact on the driver.

The conventional air bag is folded from the unfolded, plate-likeconfiguration along straight lines at predetermined positions into arectangular configuration which can be housed in the cover body.However, considerable manpower is required since it is difficult tomechanize the folding device. Therefore, it is also difficult to improveproductivity.

Japanese Patent Application No. 2000-502637 discloses a device forfolding an air bag that may be automated. This folding device comprisesfolding plates that are arranged in concentric circles or in a spiralconfiguration and are located opposite to the upper and lower parts ofthe air bag. The air bag device is inflated while it is sandwiched bythe folding plates. Each of the folding plates, which are arranged inconcentric circles, are moved or deformed to decrease the diameter ofthe concentric circles in order to fold the air bag. However, thefolding device is complicated and is costly to use.

Furthermore, an air bag that is circular as seen from a planarperspective is subject to petal folding in which the air bag is gatheredtoward its center from its outer circumference and takes on a pleat-likeconfiguration. Other structures are disclosed in Japanese UnexaminedPatent Publication No. HEI 10-129381 and Japanese Unexamined PatentPublication No. HEI 10-217894.

The present invention provides a method for folding an air bag thatprovides desired folding characteristics and can decrease manufacturingcosts, an air bag device, and an air bag.

SUMMARY OF THE INVENTION

The present invention provides a method for folding an air bag having alower panel that has a surface on one side having an inlet port intowhich gas is introduced and an upper panel that has a surface on another side located opposite to the lower panel. The method comprises aholding and inflating step, a storing step, and a pressing step.

In the holding and inflating step, the size of the air bag is adjustedso that the lower panel and the upper panel are close to each otheralong lines at predetermined positions while the air bag is inflated sothat the portions of the upper panel between the lines expand, therebyseparating the portions of the upper and lower panels between the lines.

In the storing step, the portions of the upper and the lower panelsbetween the lines are pushed toward the inlet port and folded into afolded part.

In the pressing step, the portions of the upper and the lower panels onthe lines are pushed against the outer circumference of the folded part.

In the method described above, the air bag is held so that the portionsof the upper panel and the lower panel are close to each other on thelines directed toward the inlet port at predetermined positions whereasthe portions of the upper panel and the lower panel between the linesare not held and are separated from each other. The portions of theupper panel and the lower panel between the lines are pushed toward theinlet port and are folded so that the portions of the upper panel andthe lower panel are not touching each other, and each panel is folded ina wave-like configuration to collectively form a folded part. Theportions of the upper and the lower panels on the lines are pushedagainst the outer circumference of the folded part. Therefore, the gasintroduced from the inlet port is supplied effectively to a peripheralpart of the air bag, so that the air bag inflates efficiently.Furthermore, since the height of the entire surface of the air bag isnot held in place when the air bag is folded, a large componenttypically found in conventional folding devices for holding the entiresurface in place is not required. Therefore, the air bag may be foldedquickly with a device having a simple structure, and manufacturing costsare decreased.

The holding and inflating step can comprise separate holding andinflating steps. In the holding step, the portions of the upper paneland the lower panel on the lines directed toward the inlet port areclose to each other. In the inflating step that follows the holdingstep, the portions of the upper panel and the lower panel between thelines are separated. When the holding step is performed before theinflating step, the force applied to the air bag that is required duringthe holding and inflating step is not necessary. When the inflating stepis performed before the holding step, the inner pressure of the air bagcan be increased so that the portion of the lower panel between thelines is separated quickly and substantially from the portion of theupper panel between the lines.

The method for folding the air bag can comprise a holding, supporting,and lifting step, a storing step, and a pressing step.

In the holding, supporting, and lifting step, the air bag is held sothat the portions of the upper panel and lower panel on the linesdirected toward the inlet port are close to each other. A portion of theupper panel located opposite to the inlet port is supported, and aportion of the upper panel is lifted thereby partially separating theportion of the lower panel from the portion on the upper panel.

In the storing step, the portions of the upper and the lower panelsbetween the lines are pushed toward the inlet port and folded into afolded part.

In the pressing step, the portions of the upper and the lower panels onthe lines are pushed against the outer circumference of the folded part.

In the method described above, the air bag is held so that the portionsof the upper panel and the lower panel are close to each other on thelines directed toward the inlet port at predetermined positions whereasthe portions of the upper panel and the lower panel between the linesare not held in place and are partially separated from each other. Theportions of the upper panel and the lower panel between the lines arepushed toward the inlet port and are folded so that the portions of theupper panel and the lower panel are not engaged with each other, andeach panel is folded in a wave-like configuration to collectively form afolded part. The portions of the upper and the lower panels on the linesare pushed against the outer circumference of the folded part.Therefore, the gas introduced from the inlet port is suppliedeffectively to a peripheral part of the air bag, so that the air baginflates efficiently. Furthermore, since the height of the entiresurface of the air bag is not held in place when the air bag is folded,a large component typically found in conventional folding devices forholding the entire surface in place is not required.

The method for folding the air bag can comprise a shifting step. In theshifting step, the air bag can be reshaped into the desiredconfiguration. The upper panel is moved closer to the lower panel sothat the folded air bag can be accommodated more easily. A portion ofthe upper panel that is moved overlaps without engaging the portion thatis folded during the storing step and pressing step. Therefore, the airbag can inflate quickly and immediately after the inflow of the gas.

The method for folding the air bag can comprise a hold alleviating stepwhich occurs after the storing step and before the completion of thepressing step. In the hold alleviating step, the portions of the upperpanel and the lower panel on the lines are no longer positioned close toeach other. Therefore, the air bag can be folded efficiently.

The upper and the lower panels of the air bag are approximatelycircular, and the inlet port is arranged approximately at the center ofthe lower panel. Therefore, the structure of the air bag is appropriatefor the steering wheel of an automobile.

The method for folding the air bag can comprise a storing step whereinthe exhaust of the gas inside the air bag is regulated in order toensure a slight amount of gas inside the air bag. A slight amount of gasis required for folding the air bag. As compared with the structure inwhich the air bag is inflated, less time is required to supply the gasto and exhaust the gas from the air bag. Therefore, components may beomitted or simplified in order to improve productivity.

The device for folding the air bag has a lower panel provided with aninlet port to which gas is introduced and an upper panel locatedopposite to the lower panel. The device comprises a table for placingthe air bag; inflating means for introducing the gas into the air bag;storing means for folding the air bag toward an inlet port from aperipheral part of the air bag; a guide member; and shifting means. Theguide member is located between the storing means and allows theportions of the upper panel and lower panel on the lines directed towardthe inlet port to be close to each other. The shifting means pushes thecenter part of the upper panel that is projected from the folded parttoward the inlet port.

In the folding device, the air bag is held in place by the guide memberso that the portions of the upper panel and the lower panel are close toeach other on the lines directed toward the inlet port at predeterminedpositions whereas the portions of the upper panel and the lower panelbetween the lines are not held in place and are partially separated fromeach other. The portions of the upper panel and the lower panel betweenthe lines are pushed toward the inlet port and are folded so that theportions of the upper panel and the lower panel are not engaged witheach other, and each panel is folded in a wave-like configuration tocollectively form a folded part. The portions of the upper and the lowerpanels on the lines are pushed against the outer circumference of thefolded part. Therefore, the gas introduced from the inlet port issupplied effectively to a peripheral part of the air bag, so that theair bag inflates efficiently. Furthermore, since the height of theentire surface of the air bag is not held in place at the time ofstoring the air bag, a large member becomes unnecessary which isrequired to hold the entire surface in place so that the work of swiftlyfolding the air bag with a device having a simple structure becomespossible, and the manufacturing costs are decreased. Furthermore, theair bag is reshaped in a desired configuration with the shifting means,so that the folded air bag can be accommodated more easily while aportion of the upper panel that is moved overlaps without engaging thefolded part of the air bag.

The folding device can comprise a table for placing the air bag;inflating means for introducing the gas into the air bag; storing meansfor folding the air bag toward the inlet port from a peripheral part ofthe air bag; and a guide member. The guide member is provided with afirst guide part located between the storing means and allows the upperpanel and the lower panel to be close to each other along lines directedtoward the inlet port. A second guide part is located at the inlet portside of the first guide part and allows for the accommodation forstoring the folded air bag.

In the folding device, the air bag is held in place by the first guidepart of the guide member so that the portions of the upper panel and thelower panel are close to each other on the lines directed toward theinlet port at predetermined positions whereas the portions of the upperpanel and the lower panel between the lines are not held in place andare separated from each other. The portions of the upper panel and thelower panel between the lines are pushed-toward the inlet port by thesecond guide part of the guide member and are folded so that theportions of the upper panel and the lower panel are not engaged witheach other, and each panel is folded in a wave-like configuration tocollectively form a folded part. Therefore, the gas introduced from theinlet port is supplied effectively to a peripheral part of the air bag,so that the air bag inflates efficiently. Furthermore, since the heightof the entire surface of the air bag is not held in place at the time ofstoring the air bag, a large member becomes unnecessary for holding theentire surface in place, the folding device is fast and has a simplestructure, and the manufacturing costs are decreased.

The folding device can comprise a table for placing the air bag;supporting and lifting means for supporting the central portion of theupper panel located opposite to the inlet port to partially separate thelower panel from the upper panel; storing means for folding the air bagtoward the inlet port from the peripheral part of the air bag; a guidemember; and shifting means. The guide member is located between thestoring means and allows the portions of the upper panel and lower panelon the lines directed toward the inlet port to be close to each other.The shifting means pushes the center part of the upper panel that isprojected from the folded part toward the inlet port.

In the folding device, the air bag is held in place by the guide memberso that the portions of the upper panel and the lower panel are close toeach other on the lines directed toward the inlet port at predeterminedpositions whereas the portions of the upper panel and the lower panelbetween the lines are not held in place and are separated from eachother. The portions of the upper panel and the lower panel between thelines are pushed toward the inlet port and are folded so that theportions of the upper panel and the lower panel are not engaged witheach other, and each panel is folded in a wave-like configuration tocollectively form a folded part. Therefore, the gas introduced from theinlet port is supplied effectively to a peripheral part of the air bag,so that the air bag inflates efficiently. Furthermore, since the heightof the entire surface of the air bag is not held in place at the time ofstoring the air bag, a large member becomes unnecessary for holding theentire surface in place, the folding device has a simple structure andfolds-air bags quickly, and the manufacturing costs are decreased.Furthermore, the air bag is reshaped in a desired configuration with theshifting means, so that the folded air bag can be accommodated moreeasily while a portion of the upper panel that is moved overlaps withoutengaging the folded part of the air bag.

The folding device can comprise supporting and lifting means thatcomprise a gas generator constituting an air bag device. The gasgenerator can be provided separately from the air bag and assembledinside the folded air bag. The manufacturing cost of the air bag isreduced.

The folding device can comprise exhaust regulating means for regulatingthe exhaust of the gas from the air bag. When a slight amount of gas ispresent inside the air bag, the air bag can be folded. This modificationresults in the faster supply and exhaust of gas to the air bag andallows components to be removed or simplified to improve productivity.

The folding device can comprise pressing means for reshaping the air baginto a desired configuration by pressing the portions of the upper andthe lower panels on the lines that are held in place against the outercircumference of the folded part of the air bag. Therefore, the foldedair bag can be accommodated easily into a vessel.

An air bag comprises a lower panel that serves as the surface portion onthe one side that includes an inlet port to which the gas is suppliedand an upper panel that serves as the surface portion on the other sidelocated opposite to the lower panel. The upper and lower panels are notengaged substantially with each other and are folded in independentwave-like configurations toward the inlet port while ear partscomprising the portions of the upper and lower panels on the linesdirected toward the inlet port are flattened along a spiralconfiguration on the folded part. Since the upper and lower panels inthe ear parts are not engaged with each other, the gas flows to the endof the ear parts from the inlet port through the peripheral part, andthe ear parts can be wound back. Therefore, the inflation process isimproved.

The portion of the upper panel of the air bag located above the inletport can be arranged in a single-layered, planar configuration so thatthe gas supplied from the inlet port can be transferred efficiently tothe outer circumference of the central part of the folded air bag andthe ear parts.

The air bag can comprise a front surface development part on the centralportion of the upper panel that can be inflated swiftly toward the frontsurface side immediately after the inflow of the gas to break a coverbody that covers the folded air bag and inflate the air bag efficiently.

The air bag can be further characterized since the upper panel of theair bag is not folded with the lower panel. Therefore, the gas suppliedfrom the inlet port is transferred efficiently through the air bag,thereby improving the inflation process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a folding step following FIG. 6 for a method for folding anair bag, an air bag device, and an air bag according to the presentinvention; FIG. 1(a) is an explanatory view; FIG. 1(b) is a sectionalview taken along line I-0-II of FIG. 1(a);

FIG. 2 is a perspective cutaway view of a retainer assembled in an airbag;

FIG. 3 is a perspective view of a part of a folding device;

FIG. 4 is a perspective view of a folding step of an air bag;

FIG. 5 is an explanatory view of a folding step following FIG. 4;

FIG. 6 is an explanatory view of a folding step following FIG. 5;

FIG. 7 is an explanatory view of a folding step following FIG. 1;

FIG. 8 is an explanatory view of a folding step following FIG. 7;

FIG. 9 is an explanatory view of a folding step following FIG. 8;

FIG. 10 is a perspective view of FIG. 9;

FIG. 11 is an explanatory view of a folding step following FIG. 9;

FIG. 12 is a sectional view taken along line III-III of FIG. 11;

FIG. 13 is a perspective view of FIG. 12;

FIG. 14 shows a folding step of an embodiment of the present invention;FIG. 14(a) is an explanatory view; FIG. 14(b) is a sectional view takenalong line I-0-II of FIG. 14(a);

FIG. 15 is an explanatory view of a folding step following FIG. 14;

FIG. 16 is a perspective view of an air bag during the folding process;

FIG. 17 is a perspective view of a folding configuration of an air bag;

FIG. 18 shows a folding step following FIG. 20 for a method for foldingan air bag, an air bag device, and an air bag according to an embodimentof the present invention; FIG. 18(a) is an explanatory view; FIG. 18(b)is a sectional view taken along line I-0-II of FIG. 18(a);

FIG. 19 is an explanatory view of a folding step in which a gasgenerator is assembled in an air bag;

FIG. 20 is an explanatory view of the folding step following FIG. 19;

FIG. 21 is an explanatory view of the folding step following FIG. 18;

FIG. 22 is an explanatory view of the folding step following FIG. 21;

FIG. 23 is an explanatory view of the folding step following FIG. 22;

FIG. 24 is a perspective view of FIG. 23;

FIG. 25 is an explanatory view of the folding step following FIG. 23;

FIG. 26 is a sectional view taken along line III-III of the folding stepof FIG. 25; and

FIG. 27 is a perspective view of a folding configuration of an air bag.

DETAILED DESCRIPTION OF THE INVENTION

A collision safety device such as an air bag device or an air bag moduleis provided on a steering wheel of a vehicle such as an automobile. Theair bag device comprises an air bag 1, a retainer 3, an attachable baseplate, a cover body that is formed of synthetic resin and can be broken,and an inflator, as shown in FIG. 2. Stud bolts 3 a can be projectedthrough the ring-like retainer 3. The inflator is a gas generator thatinjects gas into the air bag 1 which is projected substantially towardthe driver that is being protected. This direction of projection istoward the front surface side of the air bag 1. The rear surface side ofthe air bag 1 faces the steering shaft of the vehicle. At the moment ofcollision, this air bag device injects gas from the inflator andinflates the folded air bag 1. The inflation pressure of the air bag 1breaks the cover body at a predetermined tear line, and the inflated airbag projects in front of the driver to protect the driver from theimpact of the collision.

The air bag 1 is formed in a flat bag-like configuration by stitchingtogether two sheets of base cloth having approximately the same circularshape. The two sheets comprise a lower panel 11 and an upper panel 12.The air bag 1 is formed by overlapping the two sheets, stitching themtogether at a peripheral part 14, and reversing the stitched sheetsinside out via an inlet port 15. The inlet port 15 has a circularhole-like configuration for the insertion of the inflator that islocated at the center of the lower panel 11. Attachment holes 16 areformed on the lower panel 11 at the periphery of the inlet port 15 toallow the insertion of stud bolts 3 a. The attachment holes 16 arereinforced with ring-like reinforcement cloth 18. Vent holes (not shown)are formed on the lower panel 11. Furthermore, the panels 11 and 12 areformed of non-coated base cloth which is 200 g/m² using 315 denierthread formed of 6,6-nylon which is a polyamide synthetic fiber and hasa diameter of 650 mm. The non-coated base cloth is free of coatings ofelastomer or the like.

A device 21 for folding an air bag comprises a table 22, a center block23 which serves as inflation means and pressing means, movable blocks 24which serve as storing means, a lower blade 25, an upper blade 26 whichserves as a guide member, a center plate 27 which serves as shiftingmeans, and control means (not shown), as shown in FIGS. 1, 3, and 6. Thecontrol means controls the components of the folding device 21, a powersource device, and a driving source.

The upper surface of the table 22 includes an approximately horizontaldisk. A center block 23 is located in a circular hole 22 a in thecentral part of the disk. The center block 23 comprises a column part 23a which is formed like the inflator and a peripheral part 23 b whichsurrounds the column part 23 a. The peripheral part 23 b and the columnpart 23 a are concentric, and the peripheral part 23 b is positionedlower than the surrounding column part 23 a. A rotation mechanism, whichrotates through an arbitrarily fixed angle up to approximately 90degrees, and a lifting mechanism, which moves up and down an arbitrarilyfixed distance of approximately 160 mm, are assembled in the centerblock 23. Furthermore, an air nozzle is embedded in the center block 23as air supply means for injecting air. The center block 23 can be fixedby inserting the stud bolts 3 a of the retainer 3 through a circularhole-like holding part 23 c located at predetermined intervals on thecenter block 23.

Slit parts 22 b on the table 22 are formed in a radial configurationcentering on the circular hole 22 a. Lower blades 25 having a verticalflat plate-like configuration can move up to a predetermined height fromthe disk surface of the table 22. The lower blades 25 are raised orlowered in the vertical direction within each of the slit parts 22 b.The horizontal upper surface of each lower blade 25 is a guide part 25a. The edges on the inner and outer circumference sides of the guidepart 25 a are formed in a smooth curve-like configuration.

Movable blocks 24 are located between each of the lower blades 25. Eachof the movable lower blades 25 is connected to driving means arranged onthe lower side of the table 22 via a slit (not shown) that is providedon the table 22. The movable blocks 24 are guided and driven to advanceand retreat between the vicinity of the center block 23 and theperipheral part of the table 22. Each of the movable blocks 24 forms aplanar surface having an approximately fan-like shape, and a curvedpressing surface on the inner circumference side located opposite to thecenter block 23.

The upper blades 26 are arranged lengthwise in the radial direction andare attached to the lower surface of an upper plate 29 located above thetable 22, as shown in FIG. 6. The upper blades 26 and the upper plate 29are raised or lowered together in the vertical direction. Each of theupper blades 26 is arranged above a respective lower blade 25, and eachpair is arranged to alternate with the movable blocks 24 in thecircumferential direction. The upper blades 26 have a verticalplate-like configuration in the same manner as the lower blades 25. Aguide part 26 a of the upper blade 26 is the horizontal upper surface ofthe lower blade 25. The edges on the inner and outer circumference sidesof the guide part 26 a are formed as smooth curves. Each of the upperblades 26 is approximately equal in length and thickness to the lowerblades 25. However, the height of the upper blade 26 is longer than theheight of the lower blades 25.

The upper plate 29 comprises support parts 29 b, a connection part 29 c,and a connection part 29 d. The support parts 29 d are arranged in aradial configuration and attach to each of the upper blades 26. Theconnection part 29 c on the inner circumference side of the upper plate29 connects the inner circumference ends of the support parts 29 b. Theconnection part 29 d on the outer circumference side connect the outercircumference ends of the support parts 29 b.

The guide parts 25 a and 26 a are the edges of the upper blades 26 andlower blades 25 which are located close to the air bag 1. The air bag 1experiences an appropriate resistance to sliding since the guide parts26 a and 25 a have been embossed or have been covered with elastomertape.

Eight movable blocks 24 and eight sets of upper and lower blades 26 and25 are provided, as shown in FIG. 1(a). The blades are designed inconsideration of the volume of the air bag 1.

A circular hole 29 a at the center of the upper plate 29 hasapproximately the same diameter as a disk-like center plate 27. Thecenter plate 27 is arranged inside the circular hole 29 a.

The steps for folding the air bag 1 are shown in FIGS. 1-13, and themovable blocks 24 are omitted in FIGS. 3 and 6.

FIG. 3 shows the initial state in which the center block 23 is arrangedso that the peripheral part 23 b is aligned with the disk surface of thetable 22. The lower blades 25 are lowered in the downward direction fromthe upper surface of the table 22. The upper blades 26 and the centerplate 27 are raised in an upward direction and the movable blocks 24move to the outer circumference of the table 22. The stud bolts 3 a havebeen removed in advance from the attachment holes 16 to insert theretainer 3 through the inlet port 15 into the inside of the air bag 1.

FIG. 4 shows the stationary air bag 1 spread out on the table 22. Thecolumn part 23 a of the center block 23 is inserted into the inlet port15, and each of the stud bolts 3 a is inserted into the holding part 23c. The stud bolts 3 a are fixed with a locking mechanism provided in theholding part 23 c.

FIG. 5 shows the inflating step of the holding and inflating step inwhich compressed air is blown into the air bag 1 in the direction A toform an air pillow configuration. The compressed air is supplied from anair nozzle provided on the column part 23 a. The air bag 1 is in apartially inflated state.

FIG. 6 shows the holding step in the holding and inflating step in whichthe lower blade 25 projects upward from the upper surface of the table22, and the upper blade 26 is lowered to contact the air bag 1. FIGS. 1shows the air bag 1 being sandwiched between the lower blade 25 and theupper blade 26 in order to deflate portions of the air bag 1 that liealong the line extending in the radial direction that corresponds to theposition of the upper and lower blades 26 and 25. A predetermineddistance is fixed between the guide parts 26 a and 25 a of the upper andlower blades 26 and 25 in order to hold the height of the air bag 1 inplace along the radial direction. Furthermore, the inner pressure of theair bag 1 has increased, and therefore, the portions of the air bag 1that do not lie between the guide parts 25 a and 26 a expand since theheight of those portions is not held in place. In these portions, theupper and lower panels 12 and 11 separate. However, the upper panel 12of the air bag I does not rise high enough to contact the upper plate29.

FIGS. 7-9 show a sequence of steps that comprise the storage step inwhich the movable blocks 24 are interlocked and move collectively towardthe central point O. Portions of the air bag 1 are folded by beingpressed by the movable blocks 24 toward the central point O. However,the upper and the lower panels 12 and 11 are not folded into each otherand are folded independently in a loose wave-like configuration. FIG. 10is a perspective view schematically showing the air bag 1 at anintermediate step of folding. A central part 31 rises toward the centerin a dome-like configuration. Wave-shaped fitting parts 32 are formed onthe periphery of the central part 31, and ear parts 33 are formed at theportions of the air bag 1 that are sandwiched between the upper andlower blades 26 and 25.

FIG. 11 shows the hold alleviating step in which the lower blade 25 islowered in a downward direction while the upper blade 26 remainsstationary. Therefore, the forces that compressed the ear parts 33 ofthe upper and lower panels 12 and 11 between the upper and lower blades26 and 25 are weakened at least partially. The center plate 27 and themovable blocks 24 maintain the storage configuration of the air bag 1.

In the pressing step, the center block 23 holds down the central part ofthe air bag 1 as the center block 23 rotates through a predeterminedangle in the direction C. The ear parts 33 are pulled to the side of thepressing parts 24 a of the movable blocks 24 and flattened along theouter circumference of the wave-shaped fitting parts 32. The upperblades 26 prevent the ear parts 33 from unfolding, and the foldedconfiguration of the air bag 1 is reshaped to a predetermined height.The position of the upper blades 26 can also be moved upward in the holdalleviating step.

FIGS. 12-13 show the shifting step in which the center plate 27 islowered so that the central part 31 which is inflated in an upwarddirection is pressed down to cover the folded portion of the air bag 1as a front surface development part 35. The front surface developmentpart 35 is not engaged with the other portions of the air bag 1. Thecenter plate 27 controls the height depending on a predeterminedaccommodation size. The air bag 1 is folded and reshaped to apetal-like, octagonal configuration.

The folded air bag 1 is incorporated into an air bag device thatoperates the inflator, inflates the air bag 1, and breaks the cover bodyto form a projecting outlet port. The front surface developing part 35located immediately above the inlet port 15 is inflated quickly towardthe front surface side.

The upper and lower panels 12 and 11 are not tightly folded at thestorage step. The upper and lower panels 12 and 11 are looselyintertwined in the wave-shaped fitting parts 32 and are folded in amutually independent configuration so that that the upper and lowerpanels 12 and 11 are not folded into each other substantially.Therefore, a part of the upper and the lower panels 12 and 11 overlapsover the folded air bag 1 in the radial direction.

When gas is supplied from the inflator through an inlet port 15 at thecenter of the air bag 1, the upper and lower panels 12 and 11 can beseparated easily. The ear parts 33 are flattened along the outercircumference of the wave-shaped fitting parts 32 and can be inflatedquickly. The ear parts 33, the portions of the air bag 1 which are heldin place by the upper and lower blades 26 and 25, are not intertwinedwith each other when the part is arranged along the spiral configurationshown in FIG. 13 on the outer circumference of the wave-shaped fittingparts 32. The inflation method is improved since the ear parts 33 arewound back and can be inflated easily. Therefore, the gas can besupplied to the ends of the ear parts 33, and the air bag 1 can beinflated quickly. The manufacturing cost is lower since the foldingdevice 21 and the method for folding the air bag can be automated.

The portions of the upper surface of the air bag 1 that are not pushedby the movable blocks 24 are held in place by the upper blades 26. Theheight of the other portions that are pushed by the movable blocks 24and do not contact the upper blades 26 are not held in place and arefree to expand. Since the height of the upper surface is not held inplace entirely, the upper and lower panels 12 and 11 separate from eachother during inflation of the air bag 1. Therefore, the portions of theair bag 1 at the inlet port 15 and at the peripheral part 14 are notentangled.

After the storing step in which the movable blocks 24 move toward pointO, the upper and lower blades 26 and 25 can be withdrawn. Then, thecenter block 23 rotates in order to reduce the force applied to theupper and lower panels 12 and 11, and the air bag 1 can be foldedefficiently.

Since the front surface developing part 35 is provided on the center ofthe front surface of the air bag 1, it can be used in the initial stageto break the cover body. Therefore, the gas pressure of the inflator canbe used to inflate the air bag 1 efficiently, and the size air bagdevice can be reduced. The gas pressure of the inflator can be used moreefficiently by increasing the secondary gas pressure since the primarypeak pressure can be decreased.

The upper and lower panels 12 and 11 of the air bag 1 are notsubstantially engaged. However, the upper and lower panels 12 and 11 canbe engaged partially depending on the characteristics of the upper andlower panels 12 and 11 and the operation speed of the components.Therefore, the manufacturing costs can be decreased.

The horizontal guide parts 25 a and 26 a are provided on the lower andupper blades 25 and 26 according to the invention as described above.However, the configuration of the guide parts 25 a and 26 a can bechanged to guide the air bag 1 more smoothly depending on the amount offolding that is necessary.

FIGS. 14-15 show the folding device 21 with a first guide part 25 bwhich is a horizontal surface and a second guide part 25 c incliningdownward toward the inner circumference side of guide part 25 from theinner circumference side of the first guide part 25 b. The height of theupper blade 26 is longer than the height of the lower blade 25. Ahorizontal first guide part 26 b of the upper blade 26 is locatedopposite to the first guide part 25 b of the lower blade 25, and asecond guide part 26 c of the upper blade 26 is located opposite to thesecond guide part 25 c of the lower blade 25. A horizontal surface ispositioned on the inner circumference side of the second guide part 26 cwhich is a surface inclining upward toward the inner circumference sideof the upper blade 26. The first guide parts 26 b and 25 b and thesecond guide parts 26 c and 25 c are edges at which the upper and thelower blades 26 and 25 contact the air bag 1 and have undergone anemboss process and are covered by elastomer tape or the like. The firstguide parts 26 b and 25 b and the second guide parts 26 c and 25 cprovide some resistance to sliding of the air bag 1.

FIG. 14 shows the holding step in the holding and inflating step inwhich the lower blade 25 projects upward from the upper surface of thetable 22, and the upper blade 26 is lowered to contact the air bag 1.FIG. 14(b) shows the air bag 1 being sandwiched between the lower blade25 and the upper blade 26 so that portions of the air bag 1 are deflatedin a radial configuration. In this state, a predetermined distance isfixed between the first guide parts 26 b and 25 b of the upper and lowerblades 26 and 25. The height of the air bag 1 between the first guideparts 26 b and 25 b is held in place, and the air bag 1 can slide in aradial direction.

FIG. 15 shows an intermediate state of the storing step in which themovable blocks 24 are interlocked and move collectively toward thecentral point O. Portions of the air bag 1 are folded by being pressedby the movable blocks 24 toward the central point O. However, the upperand the lower panels 12 and 11 are not folded into each other and arefolded independently in a loose wave-like configuration. The centralpart 31 rises toward the center in a dome-like configuration, andwave-shaped fitting parts 32 are formed on the periphery of the centralpart 31. Furthermore, the portions of the air bag 1 which are sandwichedbetween the first guide parts 26 b and 25 b of the upper and lowerblades 26 and 25 are pulled into the space located between the secondguide parts 26 c and 25 c. The upper and lower panels 12 and 11 betweenthe second guide parts 26 c and 25 c are not folded into each other andare folded in a wave-like configuration to form the ear parts 33.

During the pressing step, the lower blades 25 can be lowered in thedownward direction. The upper blades 26 are stationary in the samemanner as described above or can be raised in the upward direction.Then, the forces that compressed the ear parts 33 of the upper and lowerpanels 12 and 11 between the upper and lower blades 26 and 25 areweakened at least partially. The center plate 27 and the movable blocks24 maintain the storage configuration of the air bag 1. From this state,the center block 23 holds down the central part of the air bag 1 as thecenter block 23 rotates through a predetermined angle in the direction Cshown in FIG. 11, and the ear parts 33 are pulled to the side of thepressing parts 24 a of the movable blocks 24 and flattened along theouter circumference of the wave-shaped fitting parts 32.

FIG. 16 shows the shifting step in which the center plate 27 is loweredto a position located above the inlet port 15 of the lower panel 11 sothat the air bag 1 can be folded into a predetermined petal-likeconfiguration.

FIG. 17 shows the folding configuration of the air bag 1. The portion ofthe upper panel 12 located above the inlet port 15 of the lower panel 11is arranged in a planar configuration so that the gas supplied from theinlet port 15 can be transferred efficiently to the outer circumferenceof the central part 31, the wave-shaped fitting parts 32, and the earparts 33.

The upper and the lower blades 26 and 25 are held in place during theholding and inflating step after the air bag 1 is inflated. However, theheight can be controlled while the air bag 1 being inflated in order todecrease the number of steps required to operate the device.

The folding device 21 includes a column part 23 a having the inflatingmeans and a center block 23 having an air nozzle that constitutes theinflator. The retainer 3 is assembled inside the air bag 1 to fold theair bag 1. However, the air bag 1 can be folded after the inflator isassembled in the air bag 1. Therefore, the air supply means constitutingthe inflating means is not provided, and the gas present inside the airbag 1 can be used. Then, the air bag 1 is folded so that the opposingsurface portions do not fold into each other substantially.

FIGS. 18 and 27 show an air bag 1 in which the inflator 41 serves as agas generator that constitutes the supporting and lifting means and theexhaust regulation means. The inflator 41 is incorporated in advanceinto the air bag 1 without the inflating means.

The center block 23 of the folding device 21 does not include a columnpart 23 a. The center block 23 comprises a holding part (not shown) ofthe gas generator, an inflator 41, a rotation mechanism, and a liftingmechanism. The holding part of the gas generator is located on theperipheral part 23 b, and the inflator 41 is located on the holding partof the gas generator. The rotation mechanism rotates the inflator 41,and the lifting mechanism moves the inflator 41 up and down. Stud bolts3 a in the retainer 3 are inserted into attachment holes on the flange(not shown) of the inflator 41. The inflator 41 can be used instead ofthe retainer 3.

At the initial state, the disk surface of the table 22 is aligned withthe flange of the inflator 41. The flange of the inflator 41 is attachedto the peripheral part 23 b of the center block 23. The lower blade 25is lowered in a downward direction from the upper surface of the table22. The upper blade 26 and the center plate 27 are raised in an upwarddirection, and the movable blocks 24 are pulled toward the outercircumference of the table 22. The retainer 3 is inserted in advanceinto the air bag 1 through the inlet port 15 as shown in FIG. 2, and thestud bolts 3 a are removed from the attachment holes 16.

FIG. 19 shows the supporting and lifting step in the holding,supporting, and lifting step in which the stationary air bag 1 is spreadout on the table 22. A column part of the inflator 41 is inserted intothe inlet port 15 while each of the stud bolts 3 a is inserted throughthe attachment holes in the inflator 41 into the holding part 23 c. Thestud bolts 3 a are fixed with a locking mechanism provided in theholding part 23 c.

The center of the upper panel 12 of the air bag 1 is lifted by theinflator 41 and forms a ring-like space part 44 in which air is present.The inlet port 15 of the air bag 1 is approximately airtight against theinflator 41.

FIG. 20 shows the holding step of the holding, supporting, and liftingstep in which the lower blade 25 is lifted to project upward from theupper surface of the table 22, and the upper blade 26 is lowered tocontact the air bag 1. FIG. 18 shows the air bag 1 being sandwichedgently between the lower blade 25 and upper blade 26. A predetermineddistance is fixed between the guide parts 26 a and 25 a of the upper andlower blades 26 and 25 in order to control the height of the air bag 1along the radial direction.

FIGS. 21-23 show a sequence of steps that comprise the storing step inwhich the movable blocks 24 are interlocked and move collectively andquickly toward the central point O. FIG. 24 is a perspective viewschematically showing the air bag 1 at an intermediate step of folding.The movable blocks 24 move at a sufficient speed in order to force airtoward the inlet port 15. Since the inlet port 15 of the air bag 1 isapproximately airtight, the air bag 1 can inflate with the slight amountof air that is present in the ring-like space part 44. Since each of thepanels 12 and 11 is made of a cloth having a predetermined strength, thecenter of the upper panel 12 has a tendency to move upward above theinlet port 15 in a wave configuration. When the air bag 1 is pulledtoward the inlet port 15, the air in the central part of the air bag 1also forces the center of the upper panel 12 to move upward. Then, theupper and lower panels 12 and 11 separate from each other at the portionof the air bag 1 which is pressed by the movable blocks 24 toward thecentral point O and at the peripheral part of the inlet port 15. Theupper and lower panels 12 and 11 are folded independently in a loosewave-like configuration. A central part 31 rises toward the center in adome-like configuration. Wave-shaped fitting parts 32 are formed on theperiphery of the central part 31, and ear parts 33 are formed at theportions of the air bag 1 that are sandwiched between the upper andlower blades 26 and 25. Furthermore, the inner pressure of the air bag 1increases. Therefore, the portion of the upper panel 12 that is held inplace is projected upward, and the upper and lower panels 12 and 11separate from each other. However, the upper panel 12 of the air bag 1does not rise high enough to contact the upper plate 29.

FIG. 25 shows the hold alleviating step in which the lower blade 25 islowered in a downward direction. Therefore, the forces that compressedthe ear parts 33 of the upper and lower panels 12 and 11 between theupper and lower blades 26 and 25 are weakened at least partially. Thecenter plate 27 and the movable blocks 24 maintain the storageconfiguration of the air bag 1. During the pressing step, the centerblock 23 holds down the central part of the air bag 1 as the inflator 41in the center block 23 rotates through a predetermined angle in thedirection C. The ear parts 33 are pulled to the side of the pressingparts 24 a of the movable blocks 24 and flattened along the outercircumference of the wave-shaped fitting parts 32. The upper blades 26prevent the ear parts 33 from unfolding, and the folded configuration ofthe air bag 1 is reshaped to a predetermined height. The position of theupper blades 26 can also be moved upward in the hold alleviating step.

FIGS. 26-27 show the shifting step in which the center plate 27 islowered so that the central part 31 which is inflated in an upwarddirection is pressed down to cover the folded portion of the air bag 1as a front surface development part 35. The front surface developmentpart 35 is not engaged with the other portions of the air bag 1. Thecenter plate 27 adjusts the height depending on a predeterminedaccommodation size. The air bag 1 is folded and reshaped to apetal-like, octagonal configuration.

The step of supplying and exhausting the gas in the air bag 1 is notrequired in this embodiment. Each movable block 24 can be moved fasterin the storing step. Therefore, the device can be simplified and thestoring step can be completed faster, thereby improving productivity.

The ring-like space part 44 in the air bag 1 is formed on the peripheryof the inlet port 15 when the inflator 41 of the center block 23 liftsthe upper panel 12. Therefore, an appropriate amount of air is ensuredwhile the central portion of the upper panel 12 is higher than thesurrounding portion of the upper panel 12. During the storing step, theupper and lower panels 12 and 11 are not folded tightly into each otherand are folded independently in a loose wave-like configuration.Therefore, the height between the upper and the lower panels 12 and 11can be controlled so that the final tightness and folding configurationof the folded air bag 1 can be adjusted.

Additionally, an air bag can be provided on other vehicle componentsother than the steering wheel. The present invention can be applied toan air bag device on the instrument panel in front of a passenger's seatnext to the driver's seat, the rear part of the rear passenger's seat,the side part of a seat, a door, and a pillar of the vehicle to protectthe intended object from a collision or the like.

FIG. 1 shows a method for folding an air bag, a device for folding anair bag, and an air bag. The air bag 1 is held in place so that theupper and lower panels 12 and 11 draw closer to each other along linesdirected toward the inlet port 15 created by upper and lower blades 26and 25. The other portions of the upper and lower panels 12 and 11 thatdo not lie along these lines are inflated without being held in place sothat these portions of the upper and lower panels 12 and 11 areseparated from each other. The portions of the upper and lower panels 12and 11 between the lines do not engage with each other and are folded inindependently formed wave-like configurations that comprise a centralstored form. The portions of the upper and lower panels 12 and 11 thatare held in place are pressed against the outer circumference of thecentral stored form. The gas supplied from the inlet port 15 can besupplied efficiently to the peripheral part 14 of the folded air bag 1,thereby improving the inflation process.

When the holding step is performed before the inflating step, the forceapplied to the air bag 1 that is required during the holding andinflating step is not necessary. When the inflating step is performedbefore the holding step, the inner pressure of the air bag 1 can beincreased so that the portion of the lower panel 11 between the lines isseparated quickly and substantially from the portion of the upper panel12 between the lines. The increased inner pressure of the air bag 1allows the portions of the inflated air bag 1 to be held in place on thelines.

FIG. 18 shows the air bag 1 being held in place wherein the upper andlower panels 12 and 11 draw closer to each other along lines directedtoward the inlet port 15 created by the upper and lower blades 26 and25. The portions of the upper and lower panels 12 and 11 that liebetween these lines are not held in place and inflate so that the upperand lower panels 12 and 11 are separated partially from each other.These portions of the upper and lower panels 12 and 11 are pressedagainst the inlet port 15 and are folded. The gas which remains insidethe air bag separate these portions of the upper and lower panels 12 and11 so that the upper and lower panels 12 and 11 are not engaged witheach other and are folded in a wave-like configuration. The portions ofthe upper and lower panels 12 and 11 that are held in place are pressedagainst the outer circumference of the previously folded part. The gassupplied from the inlet port 15 can be supplied quickly to theperipheral part 14 of the air bag 1, and therefore, the inflationprocess is improved.

The air bag 1 can be reshaped into a predetermined configuration byperforming a shifting step wherein the upper panel 12 is moved closer tothe lower panel 11 so that the folded air bag can be accommodated moreeasily. A portion of the upper panel 12 that is moved overlaps withoutengaging the portion that is folded during the storing step and pressingstep. Therefore, the air bag can inflate quickly and immediately afterthe inflow of the gas.

The portions of the upper and the lower panels 12 and 11 on the linescan be moved apart in the hold alleviating step prior to the completionof the pressing step. Therefore, the air bag 1 can be can be foldedeasily.

The upper and the lower panels 12 and 11 of the air bag 1 areapproximately circular, and the inlet port 15 is arranged approximatelyat the center of the lower panel 11. Therefore, the structure of the airbag 1 is appropriate for the steering wheel of an automobile.

The exhaust of the gas inside the air bag 1 is regulated in order toensure a slight amount of gas inside the air bag 1. A slight amount ofgas is required for folding the air bag 1. As compared with thestructure in which the air bag 1 is inflated, less time is required tosupply the gas to and exhaust the gas from the air bag 1. Therefore,components may be omitted or simplified in order to improveproductivity.

The method for folding the air bag is performed quickly with a foldingdevice having a simple structure, and the manufacturing costs aredecreased. The air bag 1 is reshaped into a desired configuration usingthe center plate 27 which serves as the shifting means, and the foldedair bag 1 can be easily accommodated. The center part of the upper panel12 which projects from the folded portion of the air bag 1 can beinflated quickly after the gas is supplied to the air bag 1.

In the folding device as shown in FIG. 1, the air bag 1 is held in placeby the upper blades 26 serving as the guide member so that the portionsof the upper panel 12 and the lower panel 11 are close to each other onthe lines directed toward the inlet port 15 at predetermined positionswhereas the portions of the upper panel 12 and the lower panel 11between the lines are not held in place and are partially separated fromeach other. The portions of the upper panel 12 and the lower panel 11between the lines are pushed toward the inlet port 15 and are folded sothat the portions of the upper panel 12 and the lower panel 11 are notengaged with each other, and each panel is folded in a wave-likeconfiguration to collectively form a folded part. The portions of theupper and the lower panels 12 and 11 on the lines are pushed against theouter circumference of the folded part. Therefore, the gas introducedfrom the inlet port 15 is supplied effectively to a peripheral part 14of the air bag 1, so that the air bag 1 inflates efficiently.Furthermore, since the height of the entire surface of the air bag 1 isnot held in place at the time of storing the air bag 1, a large memberbecomes unnecessary for holding the entire surface in place so that thefolding device works quickly and has a simple structure, and themanufacturing costs are decreased. Furthermore, the air bag 1 isreshaped in a desired configuration with the center plate 27 serving asshifting means, so that the folded air bag 1 can be accommodated moreeasily while a portion of the upper panel 12 that is moved overlapswithout engaging the folded part of the air bag 1.

The folding device shown in FIG. 14 comprises the first guide parts 25 band 26 b and the second guide parts 25 c and 26 c. In this embodiment,the inflation process is improved since the gas supplied from the inletport 15 can be transferred easily to the peripheral part 14 of the airbag 1.

The folding device shown in FIG. 18 can comprise a portion of the upperand lower panels 12 and 11 that are separated from each other with gasremaining in the space inside of the air bag 1.

The supporting and lifting means comprises an inflator 41 that serves asa gas generator constituting the air bag device. The inflator 41 can beassembled inside the folded air bag 1, and the inflator 41 can beprovided separate from the air bag 1 so that the manufacturing cost ofthe air bag is reduced.

An inflator 41 provided in the air bag device constitutes the exhaustregulating means for regulating the exhaust of the gas from the air bag1. When a slight amount of gas is present inside the air bag 1, the airbag 1 can be folded. This modification results in the faster supply andexhaust of gas to the air bag 1 and allows components to be removed orsimplified to improve productivity.

The center block 23 of the folding device can comprise pressing meansfor reshaping the air bag into a desired configuration by pressing theear parts 33 against the central part 31 of the air bag 1. Therefore,the folded air bag 1 can be accommodated easily into a vessel.

The air bag 1 comprises a lower panel 11 that serves as the surfaceportion on the one side that includes an inlet port 15 to which the gasis supplied and an upper panel 12 that serves as the surface portion onthe other side located opposite to the lower panel 11. The upper andlower panels 12 and 11 are not engaged substantially with each other andare folded in independent wave-like configurations while the ear parts33 are flattened along a spiral configuration on the folded central part31 toward the inlet port 15. Since the upper and lower panels 12 and 11in the ear parts 33 are not engaged with each other, the gas flowssmoothly to the end of the ear parts 33 from the inlet port 15 throughthe peripheral part 14, and the ear parts 33 can be wound back.Therefore, the inflation process is improved.

The portion of the upper panel 12 of the air bag 1 located above theinlet port 15 can be arranged in a single-layered, planar configurationso that the gas supplied from the inlet port 15 can be transferredefficiently to the outer circumference of the central part 31, thewave-shaped fitting parts 32, and the ear parts 33.

The air bag 1 can comprise a front surface developing part on thecentral portion of the upper panel 12 located above the inlet port 15 ofthe lower panel 11. The folded air bag 1 is incorporated into an air bagdevice that operates the inflator, inflates the air bag 1, and breaksthe cover body to form a projecting outlet port. The front surfacedeveloping part 35 located above the inlet port 15 is inflated swiftlytoward the front surface side immediately after the inflow of the gas tobreak a cover body that covers the folded air bag and inflate the airbag efficiently.

The upper panel 12 of the air bag 1 is not folded with the lower panel11 so that the gas supplied from the inlet port 15 is transferredefficiently through the air bag 1, thereby improving the inflationprocess.

1-15. (canceled)
 16. An air bag comprising a lower surface on one side,an inlet port on the lower surface into which gas is introduced, and anupper surface on an other side located opposite to the lower surface onthe one side; wherein the lower surface and the upper surface are foldedin an entirely independent way from each other in a wave-likeconfiguration toward the inlet port, a plurality of ear parts are formedwhich spiral toward the inlet port, and portions of the upper surfaceand the lower surface in the ear part are located opposite to each otherin a linear configuration.
 17. An air bag comprising a lower surface onone side, an inlet port on the lower surface into which gas isintroduced, and an upper surface on an other side located opposite tothe lower surface on the one side; wherein the lower surface and theupper surface are folded in a substantially independent way from eachother in a wave-like configuration toward the inlet port, a plurality ofear parts are formed which spiral toward the inlet port, and portions ofthe upper surface and the lower surface in the ear part are locatedopposite to each other in a linear configuration.
 18. An air bagaccording to claim 17, wherein a center portion of the upper surfaceabove the inlet port forms substantially a single layer.
 19. An air bagaccording to claim 17, further comprising a front surface developingpart which can be inflated toward the front surface side and is locatedon the upper surface above the inlet port.
 20. An air bag according toclaim 17, wherein a center portion of the upper surface above the inletport and a center portion of the lower surface above the inlet port aredisengaged from each other.